1. Field of Invention
The invention relates to belt pulleys particularly those having replaceable rubber lagging for improving belt grip or friction, and to the open style, wing type pulley.
2. Description of Prior Art
A common form of belt pulley is made from tubing or a rolled cylinder that forms the shell of the pulley which is made in standard diameters and lengths. Where rubber lagging is to be added to improve traction, the pulley shell may be sent to a rubber company for bonding a layer of rubber to the outer surface of the cylinder. Other alternatives are available for the addition of pulley lagging, see for example my earlier U.S. Pat. Nos. 3,354,735 and 3,789,682, where strips of rubber lagging are designed for demountable securing on the pulley surface, the latter system having the advantage of permitting renewal when the lagging becomes worn or damaged.
As above noted, the solid cylindrical shell type pulley is of necessity manufactured in particular sizes, diameters and lengths, and the manufacturer is accordingly required to make a large number of different size pulleys to supply user requirements and pulley distributors are similarly required to carry a large inventory of pulleys. Another disadvantage of the solid shell type pulley is its inability to free itself from the buildup of material which is likely to occur in many applications on the inside surface of the belt and which inevitably is carried by the belt around the pulley with consequent wear and abrasion of the pulley and belt and misalignment of the belt. The so-called wing type pulley shown in some of the patents noted below provides a desired self-cleaning action but are subject to premature wear due to minimum bearing surface and are normally not designed for traction type applications and also have the same disadvantage of the solid shell type pulley, namely, the requirement to manufacture the finished pulley in a variety of sizes to supply user requirements.
The inventor is familiar with the following prior art U.S. Pat. Nos. which constitute the most pertinent art known to him and which serve to illustrate the novelty of the present invention: 177,298; 505,810; 1,040,993; 1,691,993; 2,339,069; 2,603,099; 3,046,805; 3,168,781; 3,220,272; 3,363,476; 3,392,594; 3,744,329.